/*
 * jPOS Project [http://jpos.org]
 * Copyright (C) 2000-2015 Alejandro P. Revilla
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.jpos.iso;

import org.jpos.iso.packager.XMLPackager;

import java.io.*;

/**
 * implements <b>Leaf</b> for standard fields
 *
 * @author apr@cs.com.uy
 * @version $Id$
 * @see ISOComponent
 */
public class ISOField
		extends ISOComponent
		implements Cloneable, Externalizable {

	private static final long serialVersionUID = -4053616930139887829L;
	protected int fieldNumber;
	protected String value;

	/**
	 * No args constructor
	 * <font size="-1">(required by Externalizable support on ISOMsg)</font>
	 */
	public ISOField() {
		fieldNumber = -1;
	}

	/**
	 * @param n - the FieldNumber
	 */
	public ISOField(int n) {
		fieldNumber = n;
	}

	/**
	 * @param n - fieldNumber
	 * @param v - fieldValue
	 */
	public ISOField(int n, String v) {
		fieldNumber = n;
		value = v;
	}

	/**
	 * not available on Leaf - always throw ISOException
	 *
	 * @return never returns
	 * @throws ISOException
	 */
	@Override
	public byte[] pack() throws ISOException {
		throw new ISOException("Not available on Leaf");
	}

	/**
	 * not available on Leaf - always throw ISOException
	 *
	 * @param b
	 * @return never returns
	 * @throws ISOException
	 */
	@Override
	public int unpack(byte[] b) throws ISOException {
		throw new ISOException("Not available on Leaf");
	}

	/**
	 * not available on Leaf - always throw ISOException
	 *
	 * @param in
	 * @throws ISOException
	 */
	@Override
	public void unpack(InputStream in) throws ISOException {
		throw new ISOException("Not available on Leaf");
	}

	/**
	 * @return Object representing this field number
	 */
	@Override
	public Object getKey() {
		return fieldNumber;
	}

	/**
	 * @return Object representing this field value
	 */
	@Override
	public Object getValue() {
		return value;
	}

	/**
	 * @param obj - Object representing this field value
	 * @throws ISOException
	 */
	@Override
	public void setValue(Object obj) throws ISOException {
		if (obj instanceof String)
			value = (String) obj;
		else
			value = obj.toString();
	}

	/**
	 * @return byte[] representing this field
	 */
	@Override
	public byte[] getBytes() {
		return value != null ? value.getBytes(ISOUtil.CHARSET) : new byte[]{};
	}

	/**
	 * dump this field to PrintStream. The output is sorta
	 * XML, intended to be easily parsed.
	 *
	 * @param p      - print stream
	 * @param indent - optional indent string
	 */
	@Override
	public void dump(PrintStream p, String indent) {
		if (value != null && value.indexOf('<') >= 0) {
			p.print(indent + "<" + XMLPackager.ISOFIELD_TAG + " " +
					XMLPackager.ID_ATTR + "=\"" + fieldNumber + "\"><![CDATA[");
			p.print(value);
			p.println("]]></" + XMLPackager.ISOFIELD_TAG + ">");
		} else {
			p.println(indent + "<" + XMLPackager.ISOFIELD_TAG + " " +
					XMLPackager.ID_ATTR + "=\"" + fieldNumber + "\" " +
					XMLPackager.VALUE_ATTR
					+ "=\"" + ISOUtil.normalize(value) + "\"/>");
		}
	}

	/**
	 * changes this Component field number<br>
	 * Use with care, this method does not change
	 * any reference held by a Composite.
	 *
	 * @param fieldNumber new field number
	 */
	@Override
	public void setFieldNumber(int fieldNumber) {
		this.fieldNumber = fieldNumber;
	}

	@Override
	public int getFieldNumber() {
		return fieldNumber;
	}

	@Override
	public void writeExternal(ObjectOutput out) throws IOException {
		out.writeShort(fieldNumber);
		out.writeUTF(value);
	}

	@Override
	public void readExternal(ObjectInput in)
			throws IOException, ClassNotFoundException {
		fieldNumber = in.readShort();
		value = in.readUTF();
	}
}
